The present disclosure relates generally to analyzing composite/bonded structures by using hybrid non-destructive evaluation (NDE) and digital image correlation (DIC) techniques, and more specifically to analyzing properties of a bondline inside a structure, and predicting their life during service, thus, giving the owners a valuable tool for optimization of the maintenance effort and allowing them to make cost-optimal maintenance decisions.
At least some known systems for analyzing changes in a structure prior to and during loading involve applying random (visual) patterns to a surface of the structure, imaging the pattern prior to loading, imaging the pattern during loading, and correlating (i.e., comparing) images to determine an amount of deformation or displacement in the pattern. Such systems do not enable analysis of components or features that are not visible on the surface of the structure. Accordingly, hidden features, such as a bondline within a composite structure, cannot be analyzed using such techniques/systems.
Other known systems analyze changes in a structure using X-rays. Accordingly, such systems are capable of detecting responses to loads (e.g., mechanical and/or thermal loads) within the structure. However, such systems require two separate sources of X-rays, two separate detectors, and access to opposite sides of the structure. Such limitations make analyzing internal features of the structure impractical in many situations, including during manufacturing of the structure and when the structure is in service.
Accordingly, it would be beneficial to have systems that are capable of non-destructively analyzing load responses of features within a structure in instances where access to opposite sides of the structure is not readily available.